Hydraulic differential driving mechanism.



- L-.- M510. LEVAVASSEUR. HYDRA-ULIG DIFFERENTIAL DRIVING MECHANISM.

Patented July 4, 1911. 1

LIOATIOH FILED SEPT. 4, 1908.

. I wlm'sm MUM L. M. J. C. LEVAVASSEUR. HYDRAULIC DIFFERENTIAL DRIVINGMECHANISM.

APPLICATION FILED SEPT. 4, 1908.

Patented July 4, 1911.

. win/55m m M m fi \x. m e I f c UNITED STATES PATENT OFFICE;

mton MARIE .rosnrrr cmtmnn'r Lnvavassnm'or rn'rnnux, NEAR rams, FRANCE,ASSIGNOB T0 LA socntrn nn'romnr'rnp or ru'rnaux, NEAR rams, rmcn.

HYDRAULIC mrrnamrriar. nmvr'ne mncnamsm.

Specification of Iiett e rs raten t.

Patented July 4, 1911.

Application filed September 4, 1908. Serial No. 451,742.

To all whom it may concern:

Be it known that I, Li zon MAnm Josnrn CLEMENT LEvAvAssEUn, a citizen ofthe Republic of France, and resident of Puteaux, near Paris, France,have invented, a new and useful Improvement in or Relating to HydraulicDifferential Driving Mechanisms, which improvement is fully set forth inthe following specification.

This invention relates to hydraulic mechanism applicable where both aclutching action and a differential action are required as, for example,in connecting the two driving wheels of a motor vehicle with the sourceof power.

It has been previousl proposed to substitute for ordinary di erentialgearing a hydraulic gearing or mechanism comprising two rotary pumpseach of which has two members of which one is connected to one of thedriven members or shafts while the other is connected to a commondriving wheel or shaft which is actuated by the source of power. Theinlets and outlets of the two pumps are connected together so that eachpump may either deliver liquid to or receive it from the other pump, andthus the action of the two pumps compensates for different speed ofrotation in the members driven thereby in the same degree as occurs inthe use of toothed gearing. In such a device it has also been'proposedto provide each pump with a valve-controlled by-pass with the object ofutilizing the pumps as clutches. When the by-pass valves are closed thepumps act inthe manner above described, transmitting the full power fromthe driving member to the driven members, but when the by-pass valvesare open the fluid in the pumps passes idly through the by-passages andno power is transmitted from the driving member to the driven members,the effect being the same as if the connections between the motor andthe driven members were interrupted in the usual mannor by means of amechanical clutch.

The present invention relates to a device of the character above setforth andthe object of the invention is to produce a mechanism of thiskind in which the valve mechanism controlling the by-passages is soconstructed and arranged that it may be manuall controlled during theoperation of the di erential mechanism and regardless of the rotation ofthe pump members on which the valve mechanism is carried.

The above described invention consists in the improved hydraulicdifierential driving mechanism hereinafter described and defined in thesucceedin claims.

A preferred embodiment of my invention is. illustrated in theaccompanying drawings inwhich I Figure 1 is a partial vertical sectionon the line C-C, in F ig; 2, Fig. 2 is a. vertical longitudinal sectionon line A-A, in Fig. 1, and Fig. 3 is a vertical longitudinal section ofa portion of the casing on the line B- B in Fig. l. v

In the illustrated embodiment of my invention the driving member is ashaft 6 which may be connected with a motor or any suitable sourceofpower and the driven members are respectively'a shaft 9 arranged inline with the shaft 6 and'a hollow shaft or tube 71, journaled upon theshaft 9. The two rotary pumps by which the driving member and the drivenmembers are connected together have, in common, a casing 11 which iscentrally divided by a partition 0 into two chambers in which thepistons or abutments of the pumps operate. The pistons comprise sleevese, e which are fixed respectively to the shaft 9 and. the shaft h. Thesesleeves are provided with radial slots 6 as shown in Fig. 1, for thereception of transverse vanes f which act as the pistons of the pumps.The vanes f engage the inner surfaces of the pump chambers and aremaintained in contact therewith by means of cams f which are fixed tothe casing a and the partition and which engage the inner ends of thevanes. The portion of the casing which is uppermost in the figures is.contracted radiallyso that when the vanes f are moved by the slots erelative to the surfaces of the driven members of the compartments (:3cl are gradually contracted sothat as the vanes revolve toward the u perpart of the casin the fluid between t cm is expelled. The uid expelledby the vanes in the manner above described enters bypassages 41 in theupper part of the casing 11 and, after passing a valve 1', is returned.

15 to the pump chambers at the point where the casing widens again andthe vanes move outwardly. When the valve 71 is opened, therefore, thepumps act idly to force the liquid contained therein through the opensings (Z and the by-passages. It is to be understood that the by-passagea and the spaces between the vanes f are at all times entirely filledwith oil or some other incompressible fluid. 'Under these conditions ifthe casing a be rotated by the shaft b, to which it is fixed, the shaftsg and it will not be rotated since there will be no substantial pressureagainst the vanes f tending to rotate'the pistons of the pumps. If onthe other hand, the valve 6 be closed, thereby closing the. by-passages,the casing a and the piston members of the two pumps are practicallylocked together so that both of the shafts g and It will be rotated atthe same speed as the driving shaft b.

The differential action of the mechanism is secured by providing thepumps with inlets and outlets connected together by passages g, g in thecasing. The effect of this arrangement is to permit the interchange ofthe fluid between the two pumps vso that although the sum of therotations of the two piston members is always equal, one piston may berotated faster than the other.

If for any reasoneither one of the shafts or it and its correspondingvanes f be retarded, the continuing movement of the easing a will causea backward motion of. the said vanes relative to the casing. This willcause the oil to be forced out through the opening (i by-passage a andpassage g or q and into the space between the other set of vanes f,thus. causing them to be accelerated and to accelerate the shaft. whichthey drive. a

The present invention resides particularly in the combination, with thepump ;mechanism, of the valve-mechanism which will now be described.

The valve 5, as illustrated, is a, rotary valve, arranged to turn in arecess in the,

casing a and formed with two passages j 5} corresponding respectively.with the by-passages of the two pumps. This rotary valve has a stem atone end to which is fixed a pinion p meshing with asecond pinion 0journaled upon the casing concentric with the shafts g and h. Thepiniono carries a sleeve n which has a screw thread engagement with asecond sleeve la. The sleeve is has also a screw thread engagement withan inner sleeve 1 mounted upon and fixed to the casing. The inner andouter threads of the sleeve k are differentially formed so that if thesleeve is while rotating freely with the sleeve l he movedlongitudinally it acts to rotate the sleeve n and the pinion 0, therebyrotating the pinion p and the valve 2'. The longitudinal motion isimparted to the sleeve In by means of a ring m which is mounted betweenball hearings in an annular slotted portion at the end of the sleeve 70.The ring m does not, therefore, rotate with the other parts of themechanism and it may be connected in any ordinary or suitable mannerwith suitable manually controlled devices. When the ring m 'is movedlongitudinally as above described, by the manually controlled devices,it acts therefore through the mechanism described to rotate the valve z,and, this action occurs whether the motor casing be rotating orstationary and thus the pump mechanism may be operated either to clutchand to unclutch the driven shafts from the drivingshaft or to move thevalve tola partly open position in which a certain degree of power, lessthan the full power of the motor, may be transmitted through themechanism.

The invention is not limited to the details of construction andoperation of the illustrated embodiment thereofpbut may be embodied invarious other forms within the nature of the invention and the scope ofthe following claims.

I claim:

1. A hydraulic differential driving mechanism having, in combination, arotary driving member, two rotary driven members, connections betweeneach driven member and the driving member comprising a rotary pumpprovided with a by-passage, a valve mechanism controlling both of saidby-passages simultaneously, passages between the by-passages of thepumps and manually controllable means, V independent of the rotation ofthe. pumps, for actuating the valve mechanism during the operation ofthe differential mechanism 2. A hydraulic differential drivingmechanism' having, in combination, a rotary driving member, two drivenmembers rotating coaxially with the driving. member, connections betweeneach driven member and the driving member comprising a rotary pumpprovided with a 'by-passage, cross connections between the inlets andoutlets of the two pumps to permit the interchange of fluid between thepumps, a valve mechaspecification in the presencej of two subnismcontrolling both of said by-passages scribing witnesses. simultaneously,and manually controllable means independent of the rotation of the LEONMARIE JOSEPH pumps, for actuating the valve mechanism CLEMENTLEVAHSSEUB" during the operation of the difl'erential Witnesses:

mechanism. EMILE LEOBRET,

In testimony whereof I have signed this H. C. COKE.

